Tumor is one of the main diseases harmful to human healthy, and comes second in mortalities of various diseases. A large number of clinical practices prove that, when killing tumor cells, chemo-treatment and radiation treatment simultaneously have significant damage effect on normal cells. These treatments do serious damage to the hematopoietic system and immune function of human beings, and easily lead to patients' deaths. All of the tumor cells are dependent on vascular, and angiogenesis is an important step in the growth and metastasis of a tumor. For both primary tumors and secondary tumors, angiogenesis occurs once their growth diameter is more than 2 mm, and then the tumors grow fast and the metastasis occurs. (Folkman J. what is the evidence that tumors are angiogenesis department? J Natl Cancer Inst. 1990, 82:4-6.)
At present, drugs for treating tumors could mainly be divided into three types: cytotoxic drugs, radiotherapy and chemotherapy adjunctive drugs, and angiogenesis inhibitors. Currently angiogenesis inhibitors are a type of very promising antitumor drugs.